51. A pelton turbine develops a power of 2500 kW at 200 rpm under a net head of 400m. Calculate its approximate specific speed.

- 9
- 3
- 8
- 6

52. The unit power P_{u} of a turbine developing power P under head H is equal to

- P/H
^{2.5} - P/H
^{0.5} - PH
^{1.5} - P/H
^{1.5}

53. In all reaction turbines, for maximum efficiency,

- the velocity of swirl at the entrance must be zero
- the velocity of flow at outlet must be zero
- the velocity of swirl at the outlet must be zero
- the velocity of flow at entrance must be zero
- temperature of fluid must remain constant

54. A turbine develops 500 kW power under a head of 100 m at 200 rpm. What would be its normal speed under a head of 81 m?

- 250 rpm
- 670 rpm
- 550 rpm
- 900 rpm
- 180 rpm

55. ___________ is a tangential-flow impulse turbine.

- Pelton wheel turbine
- Kaplan turbine
- Francis turbine
- Propeller turbine
- Draft tube

56. In a Francis turbine, the water

- flows out through a closed draft tube
- flows out openly
- either flows out through a draft tube or openly depending on the type of design
- neither flows out openly nor through a closed draft tube

57. Name the ratio of power available at the shaft of a turbine to the power delivered by water to the runner.

- volumetric efficiency
- overall efficiency
- mechanical efficiency
- hydraulic efficiency

58. Governing of a turbine means

- the head is kept constant under all conditions of working
- the speed is kept constant under all conditions of working
- the discharge is. kept constant under all conditions of working
- the frictional loss is kept constant under all conditions of working

59. Which of the following statement(s) is/are incorrect?

- A turbine is called impulse turbine if at the inlet of the turbine total energy is only kinetic energy
- A turbine is called reaction turbine if at the inlet of the turbine the total energy is kinetic energy and pressure energy
- The inward flow reaction turbine having radial discharge at outlet is known as Kaplan turbine

- Only iii
- Only i
- ii and iii
- i and ii

60. To generate 8100 kW under a head of 81 m while working at a speed of 540 r.p.m., what type of turbine is suitable?

- Pelton
- Francis
- Bulb
- Kaplan